Microvalve controller for pneumatically contoured support

ABSTRACT

A pneumatic support system and controller combination including pressurizable expandable chambers ( 1 ); a source of pressure and an exhaust characterized by: a unitary manifold assembly ( 14 ) including a circuit board ( 25 ); a manifold ( 27 ) and one or more microvalves ( 24 ) having a silicon based valve actuator responsive to a signal for controlling flow from said manifold with respect to one or more expandable chambers.

This application claims benefit of Provisional Application No.60/137,873, Jun. 7, 1999.

FIELD OF INVENTION

This invention relates to fluid flow controllers for pneumaticallycontoured supports and more particularly to low energy consumption fluidflow control systems for use in controlling fluid flow in apneumatically operated system having expandable fluid chambers with acontoured support surface and wherein the fluid control systems includea microvalve having a condition responsive actuator for controlling arelatively large volume of flow through a valve unit.

BACKGROUND OF INVENTION

U.S. patent application Ser. No. 08/808,511, filed Feb. 27, 1997,discloses a pneumatically controlled seating system in which anelectronic control module selectively controls energization of a valveunit for controlling air flow from a pressure source to a plurality ofpressurizable expandable fluid chambers or air cells.

The valve unit is a low energy consumption valve that is opened andclosed by a valve actuator having a low consumption of power duringoperation of the system. One suitable valve for use in such systems isshown in U.S. Pat. No. 5,447,286 wherein a piezo actuated vent valve isprovided to control the air flow through the valve unit. The piezoactuation is provided by a cantilevered member that has a layer ofceramic material bonded to a carrier plate. The ceramic material deformswhen a voltage is imposed thereon by the control module. Deformation ofthe ceramic layer will deflect the carrier plate to open and close thevalve.

Additionally, microvalves formed within silicon wafers are known asset-forth in U.S. Pat. Nos. 4,826,131; 4,895,500; 5,909,078 and5,994,816. Such valves are characterized by low energy consumption andsmall size and by including a component that is responsive to an imposedcondition to move in a manner that will control a valving element toopen and close for controlling fluid flow, e.g., to a pressurizableexpandable chamber.

One problem with systems for pneumatically contouring support surfacessuch as vehicle seats, furniture seats and pneumatically controlled bedsis how to interconnect valve control units with pressurized expandablechambers and with a pressure source in a compact and an efficientmanner.

SUMMARY OF THE INVENTION

The problem of providing a compactly arranged and easily assembled fluidflow controller for pneumatically contoured supports and such acontroller having low energy consumption is addressed in the presentinvention by incorporating a microvalve formed on a silicon wafer andselectively combined with a controller to provide multiple flow paths toexpandable fluid chambers or air cells of a seating or body supportsystem and including at least one microvalve controlled exhaust pathfrom one or more expandable chambers or air cells.

One feature of the present invention is to provide a fluid flowcontroller of the aforesaid type in which a microvalve arrangement has aprinted circuit board supporting a common manifold and one or moremicrovalves for supplying one or more expandable chambers or air cells.

A further feature is to provide such a fluid flow controller including amicrovalve on the printed circuit board that is dedicated solely toproviding an exhaust path from the common manifold when predeterminedone or more of the expandable chambers or air cells are connected by oneor more of the supply microvalves to the common manifold.

Yet another feature is to provide the common manifold as a single tubeconnected to a lock fitting on the microvalve.

Yet another feature is to provide a single tube connected to a pressuresource.

Another feature of the present invention is to provide a fluid flowcontroller of the aforesaid type in which a first microvalve arrayincludes a supply microvalve directly connected without the use oftubing to one of the expandable chambers or air cells and to a commonmanifold.

Still another feature is to commonly connect the microvalve to apressure source and a common circuit board forming an assembly with asuitable controller for electrically connecting each of the microvalvesand the pressure source for selectively or commonly pressurizing each ofthe expandable chambers or air cells during a pump up mode of operation.

Yet another feature is to provide such a microvalve array having anexhaust mode of operation from one or all of the expandable chambers orair cells provided by a microvalve exhaust valve that is connected tothe common manifold and operated to exhaust one or more of theexpandable chambers or air cells when the power supply to the pressuresource is cut-off and one or more of the microvalves is opened inaccordance with signals from the controller.

A further feature is to provide such an arrangement wherein a secondarray of supply microvalves are connected to a second plurality ofexpandable chambers or air cells and to a second common manifold havinga source of pressure connected thereto and a second exhaust microvalveconnected thereto and wherein the operation of the second array ofsupply microvalves, pump and exhaust microvalve is in accordance with adesired operating program that can be the same or different from that ofthe first microvalves.

Still another feature of the present invention is to provide such anarrangement having microvalve and pressurizable expandable chamber orair cell connections wherein the microvalve is connected to be carriedas part of the expandable chamber or air cell either externally orinternally of the expandable chamber or air cell.

A still further feature of the present invention is to provide such anarrangement having a common single tube manifold for supply ofpressurized fluid through a supply microvalve to one or more expandablechambers or cells and to provide an individual exhaust microvalve ateach expandable chamber or cell or group of expandable chambers or cellsdefining a zone of more than one expandable chambers or cells.

Yet another feature of the present invention is to provide such anarrangement having a multi-functional microvalve module wherein all thesupply microvalves are mounted on a common silicon wafer including asingle inlet; a condition responsive region in the wafer to control flowto an outlet for supplying one or more expandable chambers or air cellsand or to exhaust path from the one or more expandable chambers or aircells.

A further feature is to provide microvalve elements in such controllerswherein an actuator is provided that is condition responsive andoperative to control a valve element to control fluid flow with respectto manifolds, expandable chambers and exhausts.

A still further feature is to provide the microvalve elements of thepreceding object with a beam that is temperature responsive.

These and other features and objects will be more apparent withreference to the accompanying drawings wherein:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagrammatic view of a pneumatically operated system havingexpandable fluid chambers with a contoured support surface in a vehicleseat controlled by the fluid control system of the present invention;

FIG. 2 is a top elevational view of a microvalve, manifold and circuitboard assembly in the fluid control system of the present invention;

FIG. 3 is a side elevational view of the assembly in FIG. 2;

FIG. 4 is a diagrammatic view of a microvalve, partially sectioned;

FIG. 4A is a schematic top view of a preferred MEMS valve in a closedposition with a mechanical latching mechanism in an engaged position;

FIG. 4B is a schematic top view of the valve of FIG. 4A in the closedposition with the latching mechanism in a disengaged position;

FIG. 4C is a schematic top view of the valve of FIG. 4A in an openposition with the latching mechanism in the disengaged position;

FIG. 4D is a schematic top view of the valve of FIG. 4A in the openposition with the latching mechanism in the engaged position;

FIG. 5 is a diagrammatic view of another embodiment of the inventionwherein a supply microvalve is directly connected by a bayonet typefitting to expandable fluid chamber(s) or air cell(s) of a pneumaticallycontrolled contouring system;

FIG. 6 is a diagrammatic view showing a supply microvalve locatedinternally of an expandable fluid chamber or cell;

FIG. 7 is a fragmentary diagrammatic view showing an individual exhaustmicrovalve for each zone; and

FIG. 8 is an elevational view of a multifunctional microvalve moduleembodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

A series of air cells or bladders 1 are placed at strategic locationsabout the contour of an automotive seat 2 as shown in FIG. 1. The aircell placement is selected to coincide with key pressure points on thebody of an occupant of the seat.

In particular, plural cells 3 are positioned in the thoracic regionwhile plural cells 4 are combined in the lumbar region. To furtherfacilitate the adjustment of the seat, pairs of cells 5, 6, 7 and 8 arepositioned at either side of the back and seat as well as the front andback of the thighs respectively. Each of these cells is in directcontact with the body to provide the control system with information,which may be related to the comfort of the user.

In addition to the pairs of cells that are provided to adjust thecomfort of a user, in accordance with the present invention a pluralityof air cells 9 are formed in the headrest and a plurality of air cells10 are provided in the seat bottom.

The cells are connected to a source of pressurized fluid provided inpart by a pump 12 through a manifold assembly 14 as shown in FIG. 2. Themanifold assembly 14 and pump 12 are operated by a controller 15 such asa microcomputer 16 in response to information stored in themicrocomputer which is compared to data provided by a sensor 18.Alternatively, the controller 15 can be a switch arrangement thatselectively controls valves (to be discussed) and a power supply for thepump 12.

Each individual cell is constructed of a suitable flexible material suchas rubber, thermoplastic polyurethane-coated fabric or any othermaterial provided with a fluid tight connection to the manifold toprovide a path for conducting fluid into and out of the cell. The cellsmay be connected individually to the manifold or jointly with othercells. Individual spaced parallel cells 3,4,9, 10 are located for fullbody support and constitute a pneumatically operated system havingexpandable fluid chambers defining a contoured support surface.

While a vehicle seat is shown, such expandable fluid chambers can beused in beds, office furniture, household furniture and other occupantsupport systems having a support surface therein.

The seating or load support system can also be of the type shown incopending U.S. patent application Ser. No. 09/321,235 filed May 27, 1999and incorporated herein by reference and having a common assignee. Itshould be further understood that the invention as set-forth herein isequally suitable for use in any comfort support system that is contouredby changing the pressure within individual one or more of cells thatdefine the support surface within the system.

The manifold assembly 14 includes microvalves 24 a-24 c connected to acommon circuit board 25; a tube 27 is connected to a plurality of themicrovalves 24 by bayonet type inlet fittings 26 thereon so as tosupport the tube 27 in spaced relationship to the circuit board 25.

As seen in FIG. 4, each microvalve 24 includes an inlet or bayonet typefitting, 26, and an outlet or bayonet type supply fitting 28. Themicrovalve includes a valve plate 29 movably supported on amicroelectronic substrate 30. The valve plate 29 is responsive tosignals imposed across control lines 31 to assume a position across avalve opening 32 formed through the substrate 30 to open and close apassage 33 between the inlet 26 and the outlet 28. Such microvalves canbe of the microelectromechanical systems or MEMS type disclosed, e.g.,in U.S. Pat. Nos. 5,909,078 and 5,994,816 which are incorporated hereinby reference. Such valves include a leaf, beam or other mechanicalportion as an integrated component within a silicon chip manufactured byknown silicon fabrication techniques. In the present application, thevalve element is actuated to control fluid flow between the inlet 26 andoutlet 28. Various actuation mechanisms are applicable in MEMS typecontrol valves including magnetic, electrostatic, piezoelectric,differential pressure and thermal mechanisms. The mechanisms foroperating the valving element can include materials that are shapedmemory alloys or bi-metallic materials such as disclosed in ourcopending U.S. Ser. No. 09/143,784 filed Aug. 31, 1998. In themicrovalves used in the assembly of FIG. 2, and in other embodiments tobe discussed, electrostatic, differential pressure, and thermalactuation mechanisms are used.

Preferably, the microvalve 24 includes a thermal arched beamelectromechanical actuator of the type disclosed in U.S. Pat. Nos.5,909,078 and 5,994,816. As shown schematically in FIGS. 4A through 4D,the preferred microvalve 24 and includes a silicon valve gate 34including three rectangular grates 34 a-c integrally interconnected in aspaced-apart disposition by a coupler bar 35. The grates 34 a-c areslidably disposed over corresponding etched elongated through-holes 36in the substrate 30. The gate 34 is movable between a normally closedposition shown in FIGS. 4A and 4B and an open position shown in FIGS. 4Cand 4D. In the closed position, the grates 34 a-c close thethrough-holes 36 blocking air flow through the passage 33. In the openposition, the grates 34 a-c are clear of the through-holes 36 allowingair to flow through the passage 33. A pair of silicon arched beams 37 a,37 b are supported on the substrate 30 at respective opposite beam-endsin a perpendicular relationship to the coupler bar 35. The arched beams37 a, 37 b are connected at their approximate centers to the coupler bar35. When heated by passing electrical current through them, the beams 37a, 37 b extend in length resulting in further arching and translationalmovement of the coupler bar 35 from the closed to the open position.When they are de-energized, the beams 37 a, 37 b return to theirprevious length and shape drawing the coupler bar 35 and gate 34 back tothe closed position.

Preferably, the microvalve also includes two pairs of thermo-mechanicallatches 39 a, 39 b supported on the substrate 30 immediately adjacentand laterally flanking an outer two grates 34 a, 34 c of the threegrates 34 a-c. Each latch of the two pairs of latches 39 a, 39 bincludes a latch detent 45 shaped and positioned to engage acorresponding gate detent 47 on the outer two grates 34 a, 34 c. Eachlatch detent 45 is movable between an engaged position shown in FIGS. 4Aand 4D and a disengaged position shown in FIGS. 4B and 4C. In theirrespective disengaged positions, the latch detents 45 allow the gate 34to move between the open and closed positions. In their respectiveengaged positions, the latch detents 45 hold the gate 34 in either itsopen or closed position by engaging the respective gate detents 47. Thelatches 39 a, 39 b are actuated by passing electrical current throughthem. When electrical current is passed through the latches 39 a, 39 b,the narrower of two longitudinal parallel beams lengthens more than athicker one of the two beams. This causes the latch detents 45 to pullaway from and disengage the gate detents 47.

In operation, to open the microvalve 24, power is supplied to actuatethe latches 39 a, 39 b which then release the gate 34 as shown in FIG.4B. The beams 37 a, 37 b are then energized to drive the coupler bar 35and gate 34 to the open position. As shown in FIG. 4C, in the openposition, the grates 34 a-c are positioned clear of the through-holes36. Power is then removed to de-activate the latches 39 a, 39 b whichcauses the latch detents 45 to engage the gate detents 47 thus holdingthe gate in the open position as shown in FIG. 4D. Power is then removedfrom the beams 37 a, 37 b and the microvalve 24 remains in the open or“switched” state without power input.

To close the microvalve 24, power is supplied to actuate the latches 39a, 39 b which then release the gate 34. The de-energized unheated beams37 a, 37 b then pull the coupler bar 35 and gate 34 back to the closedposition shown in FIG. 4B. The latches 39 a, 39 b they are de-energizedand re-engage and hold the gate 34 in the closed position.

As shown in FIG. 2, the circuit board 25 is shown carrying a pluralityof microvalves 24 a-24 b that have their inlets formed as bayonet typefittings 26 directed into a common manifold tube 26 so as to support themanifold tube 26 on the circuit board 25. Outlet fittings 28 areconnected by tubing 28 a to the various cells 1-10. The manifold tube 27has an inlet end 27 a connected to a suitable pressure source such as apump as set-forth in the aforesaid '511 application. An exhaustmicrovalve 24 c is connected to the manifold tube 27 and includes aninlet 26 c, an outlet 28 c and a moveable leaf 30 c (as previouslydiscussed) that opens and closes a passage through the exhaustmicrovalve 24 c for exhausting the manifold to atmosphere through itsoutlet 28 c.

As can be seen in FIG. 3, the arrangement provides a compact controlvalve array that eliminates control wiring external of the envelope of aprinted circuit board and enables a wide array of valves to be handledas a single unit for ease of assembly with respect to expandablechambers or air cells of a pneumatically controlled support system.

In other cases it might be desirable to contain the microvalves eitheras a direct connection to a cell internally or externally thereof Onesuch arrangement is shown in FIG. 5 wherein a first array of supplymicrovalves 40 a-40 b in which each of the supply microvalves 40 a, 40 bhas its outlet 41 directly connected to one of the expandable chambersor air cells 42, 44 and having their inlets 43 connected to a supplymanifold tube 46 that is connected to a pressure source 48. A printedcircuit board 50 with a suitable controller 52 (either on the board orseparate) is electrically connected to each of the microvalves 40 a, 40b and to the pressure source 48 for supplying power to the pressuresource for selectively or commonly pressurizing each of the expandablechambers or air cells during a pump up mode. An exhaust mode from one orall of the expandable chambers or air cells is provided by a microvalveexhaust valve 53 that is connected to the common manifold tube 46 andoperated to exhaust one or more of the expandable chambers or air cellswhen the power supply to the pressure source is cut-off and one or moreof the microvalves is opened in accordance with signals from acontroller 50 a on the printed circuit board.

In the embodiment of FIG. 5 one or more exhaust valves can be provided,as can one or more pumps or pressure sources. Thus, on the other side ofthe printed circuit board 50, (if desired) a second array of supplymicrovalves 40 c, 40 d is provided. The microvalves 40 c, 40 d areconnected to a second plurality of expandable chambers or air cells 42a, 44 a and to a second common manifold 54 having a source of pressure56 connected thereto. A second exhaust microvalve 58 is connected to themanifold 54. The operation of the second array of supply microvalves,pump and exhaust microvalve is in accordance with a desired operatingprogram that can be the same or different from that of the first arrayof supply microvalves.

In the embodiment of FIG. 5, the electrical connection to the controlmodule of the printed circuit board are direct from each of the controland exhaust valves as shown at connections 55 and 57.

While the microvalve and air cell connections are shown external, ifdesired, a microvalve 59 can be connected internally of an air cell 61as shown in FIG. 6.

In the embodiment shown in FIG. 7, a common manifold 60 is provided forsupply of pressurized fluid through a supply microvalve 62 to a cell 64and an individual exhaust microvalve 66 can be provided at each cell orgroup of cells defining a zone of more than one cell.

In the embodiment shown in FIG. 8, a multi-functional microvalve module70 is shown wherein all the supply microvalves 72, 74 are mounted on thesame silicon wafer including a single inlet 76. A pressure-sensing layer78 is provided in the wafer to sense pressure in the module. A controlarea array 80 is provided on the wafer. A plurality of outlets 82-84 areprovided from the module 70 for supplying one or more cells and or anexhaust outlet 86 from the one or more expandable chambers or air cellsvia passages (not shown) in the module for connecting one or more of thecells with atmosphere. In this embodiment, the common manifold isintegral to the module. Pressure sensing is integral to the module andan open cell valve can be provided to read pressure. The output of thepressure sensor 78 is connected to the control area 80. The control area80 can either pass the pressure signal to a main controller of the typeshown in the '511 application. Alternatively, if the control area 80 iscapable, e.g., has a comparator to compare the sensed pressure to adesired pressure control setting, the control area itself can beoperative to open or close the valves to the expandable chambers or aircells based on the detected pressure. Furthermore, an output throughcontrol lines 90 may control either a remote or integral pump.

What is claimed is:
 1. A pneumatic support system and controllercombination including: a pressurizable expandable chamber; a source ofpressurized fluid connected to the chamber and configured to supplyfluid under pressure to the chamber; an exhaust connected to the chamberand configured to release fluid from the chamber; and a manifoldassembly including: a circuit board; and a microvalve supported on thecircuit board and having a valve actuator comprising silicon andconfigured to control fluid flow between the chamber and at least one ofthe source and the exhaust in response to a signal received from one ormore circuit components on the circuit board.
 2. The pneumatic supportsystem and controller combination of claim 1 in which: the microvalve isa supply microvalve that includes: an inlet connected to a manifold; andan outlet connected to the expandable chamber, the supply microvalvebeing operative to control pressurized flow from the manifold to theexpandable chamber.
 3. The pneumatic support system and controllercombination of claim 1 in which: the manifold is carried by themicrovalve; the microvalve is connected to the circuit board; and themicrovalve is operative to control pressure in the expandable chamber.4. The pneumatic support system and controller combination of claim 2 inwhich: the circuit board is a printed circuit board; the microvalve is asupply microvalve electrically connected to the printed circuit board;and the supply microvalve is operative to control pressure in theexpandable chamber in response to signals received from the printedcircuit board.
 5. The pneumatic seating or body support system andcontroller combination of claim 2 in which the manifold assemblyincludes an exhaust microvalve operative to exhaust the expandablechamber during an exhaust phase of operation.
 6. The pneumatic supportsystem and controller combination of claim 2 in which: the manifoldassembly includes an exhaust microvalve supported on the circuit board;the manifold is a common manifold configured to carry both supply andexhaust air; and the exhaust microvalve provides an exhaust flow pathfrom the common manifold when the supply microvalve connecting theexpandable chamber to the common manifold is open during an exhaustmode.
 7. The pneumatic support system and controller combination ofclaim 1 in which: the microvalve is directly connected to the expandablechamber and to a manifold; a pressure source is connected to themanifold and a controller; and the controller is electrically connectedto the microvalve and to the pressure source for pressurizing theexpandable chamber during an inflate mode.
 8. The pneumatic supportsystem and controller combination of claim 1 in which: a first array ofsupply microvalves is connected to a first plurality of expandablechambers and to a first common manifold having a source of pressureconnected thereto; a second array of microvalves is connected to asecond plurality of expandable chambers and to a second common manifoldhaving a source of pressure connected thereto; and the operation of thesecond array of supply microvalves is in accordance with a desiredoperating program that can be the same or different from that of thefirst array of supply microvalves.
 9. The pneumatic support system andcontroller combination of claim 1 in which one or more microvalves isconnected to be carried on the expandable chamber as part of theexpandable chamber either externally or internally of the expandablechamber.
 10. The pneumatic seating or body support system and controllercombination of claim 1 further including: a common manifold configuredto supply pressurized fluid through one or more microvalves to one ormore expandable chambers, the one or more microvalves each supplying oneexpandable chamber or a group of expandable chambers.
 11. The pneumaticsupport system and controller combination of claim 1 further including amulti-functional microvalve module, the microvalve module comprising:the microvalve; a silicon wafer supporting the microvalve, themicrovalve including a single inlet in the wafer, the wafer including: apressure sensing layer; a control logic array; and an outlet forsupplying the expandable chamber and or a flow path from the expandablechamber.
 12. The pneumatic support system and controller combination ofclaim 1 in which the microvalve includes a thermal arched beamelectromechanical actuator configured to open and close the microvalve.13. The pneumatic support system and controller combination of claim 1in which the microvalve includes a silicon valve gate including a firstgrate slidably disposed over a first set of corresponding etchedthrough-holes in the substrate, the gate being movable between a closedposition closing the first set of through-holes and an open position atleast partially opening the first set of through-holes.
 14. Thepneumatic support system and controller combination of claim 13 in whichthe valve gate includes at least one additional rectangular gratecoupled to and movable with the first grate between a closed positionclosing a second set of corresponding through-holes etched in thesubstrate and an open position at least partially opening the second setof through-holes.
 15. The pneumatic support system and controllercombination of claim 14 further including a silicon arched beamelectromechanical actuator supported on the substrate, coupled to thevalve gate and configured to drive the valve gate between the closed andopen positions.
 16. The pneumatic support system and controllercombination of claim 15 in which: the valve gate is normally in theclosed position; and the actuator is configured to drive the valve gatefrom the closed toward the open position when electrical current throughthe arched beam actuator is increased and to allow the valve gate tomove back toward the closed position when electrical current through thearched beam actuator is decreased.
 17. The pneumatic support system andcontroller combination of claim 15 in which: the valve gate includes acoupler bar mechanically coupling the first grate to the second grate;and the arched beam actuator is drivingly coupled to the coupler bar.18. The pneumatic support system and controller combination of claim 13in which the microvalve includes a thermo-mechanical latch supported onthe substrate and configured to engage and hold the gate in the openposition when the gate is moved to the open position.
 19. The pneumaticsupport system and controller combination of claim 18 in which the latchis configured to release the gate from the open position when sufficientelectrical current is passed through the latch.
 20. The pneumaticsupport system and controller combination of claim 13 in which themicrovalve includes a thermo-mechanical latch supported on the substratefor movement between a disengaged position allowing the gate to movebetween the open and closed positions and an engaged position holdingthe gate in either its open or closed position.
 21. The pneumaticsupport system and controller combination of any of claims 18-20 inwhich: the latch includes two longitudinal parallel beams of differingthickness; and the latch moves out of the engaged position in responseto the proportionately greater lengthening of the thicker of the twobeams in response to an electrical current being passed through thelatch.